Solvent Extraction of Klebsiella pneumoniae Bacteriophage Lysates with 1-Dodecanol Results in Endotoxin Reduction with Low Risk of Solvent Contamination.

Antimicrobial resistance in pathogenic bacteria is increasing worldwide. One solution to this crisis is bacteriophage therapy, a treatment that harnesses naturally occurring bacterial viruses to invade and lyse antimicrobial resistant bacterial hosts. In Gram-negative hosts, a by-product of bacteriophage production is bacterial endotoxin, which can cause serious immune reactions in vivo. Purification methods using organic solvent extraction can remove endotoxin in bacteriophage lysates. In this study, we investigate a method for removal of endotoxin from 16 high-titer Klebsiella pneumoniae lysates by extraction with 1-dodecanol, 1-octanol, dodecane, or decane. In these experiments, treatment with either 1-dodecanol or 1-octanol resulted in removal of 104-105 endotoxin units/mL. Recovery of bacteriophage in lysates treated with dodecanol without dialysis was >90%, and residual dodecanol was low (10-1500 ppm). Overall these results suggest that organic solvent extraction using 1-dodecanol is effective at removing bacterial endotoxin, maintaining bacteriophage titer, and reducing solvent contamination in 16 K. pneumoniae bacteriophage lysates.